Regenerator disk flexible rim

ABSTRACT

A flexible rim for a regenerator disk is provided by a spirally wound corrugated sheet having the peaks of the ridges of corrugations thereof partly crushed downward toward the hollows of the corrugations along crush paths extending at an angle from one edge of the sheet across the sheet, the wraps of the sheet being bonded together and to the main heat transfer matrix of the regenerator disk. The flexible rim can be used as the rim, per se, of the regenerator disk, or as a connector between the main heat transfer matrix of the regenerator disk and an outer rigid rim thereof.

United States Patent 1191 Thebert Aug. 26, 1975 [5 REGENERATOR DISKFLEXIBLE RIM 75 Inventor: Glenn w. Thebert, Carmel, Ind. Dav,

Attorney, Agent, or F1rmArthur N. Kreln [73] Assignee: General MotorsCorporation,

v Detro1t, M1ch. [57] ABSTRACT [22] F1160: May 1974 A flexible rim for aregenerator disk is provided by a [21] Appl. No.2 470,533 spirally woundcorrugated sheet having the peaks of the ridges of corrugations thereofpartly crushed downward toward the hollows of the corrugations [52]:J.S.CCI l6i/288,dli g/(l)3 along Crush paths extending at an angle fromone edge [51] nt. l. 9/ of the Sheet across the sheet, the wraps of theSheet [58] Field of Search 165/8, 10 being bonded together and to themain heat transfer matrix of the regenerator disk. The flexible rim canbe [56] References and used as the rim, per se, of the regenerator disk,or as a UNITED STATES PATENTS connector between the main heat transfermatrix of 2,596,642 5/1952 Bocstad 165/10 X the regenerator disk and anouter rigid rim thereof. 3,511,309 5/1970 Clifford ct a1. 165/10 x3,534,807 10/1970 Bracken, Jr 165/10 x 6 Clalms, 4 Drawmg Flgul'esREGENERATOR DISK FLEXIBLE RIM This invention relates to a regeneratordisk for a rotary regenerator heat exchange apparatus and, inparticular, to a flexible rim encircling the main heat transfer matrixcore of a regenerator disk.

Rotary regenerators, particularly of the axial flow type as used in gasturbine engines, utilize heat transfer means in the form of a porousmetal disk matrix which is rotated so that each element thereof passessuccessively through two aeriform fluid flow paths, absorbing heat froma hotter fluid and releasing it to a cooler fluid in these flow paths.

Metal matrices ordinarily are made up of crimped or corrugated metalsheets spirally wound into a disk and then brazed or otherwise bondedtogether so as to provide a rigid cellular or porous structure. Thisrigid cellular or porous structure is normally enclosed at at least theouter peripheral edges thereof by outer sealing rings or an outer ringwhich provide a solid rim around the periphery of the matrix.

In regenerators of the type to which this invention is particularlyapplicable as used in gas turbine engines, the major portion of the diskis heated to relatively high temperatures of the order of up to 1,450F.or higher, whereas the rim or radially outermost portion of the disk iscontacted around the perimeter by the relatively cool air and thus is atsubstantially lower temperature. In addition, the regenerators are alsocycled between cool and hot conditions when the engine is started andstopped. Other factors may cause temperature gradients but, in general,whatever the reasons for the differences in temperature betweendifferent radial zones of the matrix, the result is differentialexpansion with attendant overstressing and yielding of the parts andresulting cracking.

The conventional inner core structure or main heat transfer body of suchan axial-flow regenerator matrix disk involves alternating flat andcorrugated strips or alternating corrugated strips which are spirallywound to form the main heat transfer body of the matrix. One example ofsuch an alternating flat strip and corrugated strip structure isillustrated in U.S. Pat. No. 3,276,515 for Gas Turbine Regeneratorissued Oct. 4, 1966 to James H. Whitfield. In a structure of this sort,the matrix is quite rigid once the strips are brazed together. althoughthe corrugated strip can give, the flat strip between the layers ofcorrugated strip is substantially unyielding. An example of alternatingcorrugated strips structure is illustrated in U.S. Pat. No. 3,532,157entitled Regenerator Disk issued Oct. 6, 1970 to William S. Hubblewherein a corrugated or weakened sheet layer is substituted for the flatsheet layer in an attempt to correct the problem encountered in the useof the flat sheet layer.

Using such matrix structures, it is conventional to provide a rim aroundthe matrix disk of the regenerator against which the conventional rimseals of the regenerator will bear. Accordingly, a primary object ofthis invention is to provide a regenerator disk with a rim which iscircumferentially flexible.

It may also be desirable to form a regenerator disk with a rigid outerrim and to provide a suitable connector between this rigid rim and themain heat transfer body of the regenerator disk, the connector beingused as a connection between these elements to provide for alignmentbetween the main heat transfer body and the rigid rim and to providesome transmission of torque between these elements. Thus, if the matrixis rotated by a central shaft and the regenerator seals bear against theouter rim, there needs to be a connection between the main body of thematrix and the rim to assure joint rotation of theseparts. In othercases, the connection may be between the heat transfer body or core ofthe matrix and a rim in the form of a driving gear from which torque istransmitted to rotate the matrix.

A primary object of this invention is to provide a flexible connectorrim for use in a rotary regenerator matrix to interconnect the main heattransfer body of the matrix .to a rigid outer rim.

Another object of this invention is to provide a regenerator matrix, themain body of which is formed by spirally wound corrugated strips, one ofthe strips then being further spirally wound, with the corrugations ofthe strip partly crushed to provide a flexible interconnection betweenthe main body of the matrix and an outer rim.

A further object of this invention is to provide a flexible rimconnection between inner and outer parts, the flexible rim being used tocenter the parts relative to each other and to provide for transmissionof torque therebetween while allowing the parts to conform to each otherwith low interface loading therebetween.

A still further object of this invention is to provide a regeneratormatrix having an inner core of heat transfer material and an outer rimformed by a spirally wound sheet having uniform corrugations, the ridgesof which are partly crushed along crush paths, the sheet being wound asufficient number of turns and secured together and to the inner core toprovide an outer rim of the desired radial width, the rim structureproviding circumferential flexibility while conforming to the innercore.

These and other objects of the invention are obtained by a flexible rimencircling the main heat transfer body or core of a regenerator matrix,the flexible rim being fabricated as a spirally wrapped, corrugatedstrip with angled crush paths formed in portions of the peaks of thecorrugations of the sheet to prevent nesting of the overlapping layersof the sheet. The flexible rim can be used as the rim, per se, of thematrix, when made a predetermined radial width or as a connectionbetween the main heat transfer body of the regenerator disk and an outerrigid rim.

For a better understanding of the invention, as well as other objectsand further features thereof, reference is had to the following detaileddescription of the invention to be read in connection with theaccompanying drawings, wherein:

FIG. 1 is an axonometric view of an axial flow regenerator matrix;

FIG. 2 is a detailed sectional view, on an enlarged and exaggeratedscale, taken on a radial plane indicated by the line 2-2 in FIG. 1;

FIG. 3 is a sectional view, in exaggerated scale, taken perpendicular tothe axis of the matrix as indicated by the line 3-3 in FIG. 2; and,

FIG. 4 is a perspective, enlarged and exaggerated view of the crushedcorrugated strip used to form the flexible rim structure of theregenerator matrix.

Referring now to the drawings, there is shown in FIG. 1 an axial flowregenerator matrix 10 which, except for the invention incorporatedtherein, as will be described, may be of a conventional or known typesuited for use in regenerators of the type shown in US. Pat. No.3,368,611 for Rotary Regenerator Seal with High Pressure Fluid Recoveryissued Feb. 13, 1968 to Joseph W. Bracken, Jr., and Richard M. Zeek.Since such a regenerator matrix may be over two feet in diameter with athickness of only about three inches, it will be apparent that theillustration thereof in FIG. 1 is exaggerated to show the separateelements, to be described, of this structure.

The matrix 1.0, as seen in FIG. 1, includes a cylindrical hub 11 whichmay include means (not shown) for connecting the hub to a matrix drivingshaft, such as disclosed in US. Pat. No. 3,476,173 for RotaryRegenerator Matrix Mount and Drive issued Nov. 4, 1969 to Joseph W.Bracken, Jr., and William S. Hubble. The matrix further includes acylindrical or diskshaped main body or inner core 12 of heat transfermaterial which may be defined by alternating flat and corrugated stripsor, preferably, by alternating deeply corrugated and shallow corrugatedstrips of thin sheet metal wrapped spirally around the hub so as todefine passages extending generally axially of the matrix through thecorrugations. The main heat transfer body of the matrix thus comprisesthe inner core 12 extending from the hub 11 to a dividing cylindricalsurface or boundary 14, indicated by broken line in FIG. 1. The matrix10 may also include an outer rigid rim, herein shown as a one-piece sealring 16 with which the rim seals, not shown, of the regeneratorcooperate, which extends around the periphery of the inner core 12 ofthe matrix and is spaced radially from it and connected to it by aflexible rim, generally designated 20, constructed in accordance withthe invention, that extends from boundary 14 radially outward, apredetermined radial width.

As best seen with reference to FIGS. 2, 3 and 4, the flexible rim 20 ofthe regenerator matrix, in accordance with the invention, when used as aconnector is formed by at least two spiral coils or wraps of a strip 22having somewhat triangular shaped, deep corrugations with regular andequally curved ridges and hollows, the corrugations trending axially ofthe matrix, the peaks of the ridges of the corrugations being crushed asat 22a in relatively narrow, overlapping paths to provide crushed tracksangled at an angle other than a right angle from the edges of the stripand extending there-' across, whereby the crushed tracks will extendacross a plurality of corrugations. Preferably, a portion of each peakof a ridge of a corrugation is crushed so that this otherwise peakportion of the corrugation is deformed downward into the valleys orhollows on opposite sides of the ridge to lie substantially in the sameplane as the hollows of the corrugations, that is, the plane of thesheet material forming the base or the ho]- lows of the corrugations. Itwill be seen with reference to FIG, 2 that the angled crushed tracks inthe outermost wrap of sheet 22, the upper wrap with reference to thisfigure, will prevent nesting of the corrugations on the next wraptherein, since a portion of each of the peaks of the corrugations onthis next wrap, the lower wrap with reference to FIG. 2, will abutagainst the crushed portions of the outer wrap. The wraps of the sheet22 with the angled crushed paths thereon would be secured together as bybrazing to each other and to the inner core 12 to form an integral heatexchange matrix structure.

So as to retain the advantages of the corrugated sheet 22, which may,for example, be as little as only three inches wide to correspond to theaxial thickness of the regenerator disk, the crushed tracks arerelatively nar row and in order to prevent the formation of a continuouscircumferential high strength band, each crushed track is angled toextend across only a limited number of corrugations. As best seen inFIG. 4, a crushed track starts at one edge of the sheet and extends atan angle thereacross to run out at the opposite edge, with the nextcrushed track then partly overlapping circumferentially the first track,but being axially spaced therefrom with reference to the axis of thematrix structure.

The flexible rim 20, as described, could be formed as a separate elementand then used to connect two parts, such as the main body of a matrix toan outer rim. However, in the preferred embodiment of a regeneratordisk, as shown, the main heat transfer body or inner core 12 thereof isfabricated of alternating turns of a first strip 22 having relativelylarge corrugations trending axially of the matrix and a second orseparator strip 24 having relatively small corrugations trending axiallyof the matrix. The direction of the corrugations is the same on bothstrips. However, as will be apparent from FIG. 2, the corrugations onthe first strip 22 have ap proximately three times the width and aboutsix times the depth of the corrugations on the second or separator strip24, these two strips would be spirally wound around the hub 11 to theradial boundary 14 and suitably secured together as by brazing to forman integral inner core. After this, the second or separator sheet 24 isno longer used, but the free end of the first strip 22 with its deepcorrugations is then crushed in a suitable manner whereby the strip 22now forms the strip 22 with its crushed 22a tracks and then this strip22 is spirally wound a suitable number of turns around the inner core 12to provide the flexible rim 20, after brazing or otherwise securing thethus wrapped sheet 22 together and to'the inner core 12. The rim 20 willthus provide a low spring rate band which conforms to the inner core 12.The rim 16 can thereafter be connected to the main heat transfer body 12of the matrix with the rim 20 as the connector therebetween in anysuitable manner as, for example, by the use of radial extending pins,not shown, coupling the rim 16 to the rim 20 in the manner disclosed inU.S. Pat. No. 3,534,807 for Regenerator Rim Spacer issued Oct. 20, 1970to Joseph W. Bracken, Jr., which is incorporated herein by reference.

Although in the embodiment illustrated, the flexible rim 20 is used as aconnector between the main heat transfer body or inner core 12 and theouter rigid rim 16, in an alternate embodiment of the invention, notspecifically illustrated since it can readily be described withreference to FIG. 1, the outer rim 16 is not used and, instead, the rim20 is fabricated with sufficient spiral wraps of the sheet 22 with thecrushed tracks across its corrugation to form a rim structure ofsufficient radial width to provide the rim, per se, of the regeneratordisk matrix. That is, the regenerator matrix 10, in this embodiment,would only include the hub 11, inner core 12 and rim 20. Thus, the rim20, fabricated with the spirally wound, corrugated strip sheet 22 withthe curshed 22a tracks thereon, can be used to provide a rim, per se,ofa radial width corresponding, for example, to the radialwidth of thesealing outer rim 16 plus the radial width from boundary 14 to the innercylindrical edge of outer rim 16, with reference to FIG. 1. For example,using a sheet 22 of stainless steel approximately 0.002 inch thick, withoriginally uniform corrugations of from 0.060 to 0.130 inch deep (theradial dimension of the corrugations transverse to the general plane ofthe strip sheet), and with the crushed 22a tracks formed thereon, thesheet 22 could be spirally wrapped a sufficient number of turns and thenbonded together and to the inner core 12 to provide, for example, a 0.75inch radial wide rim with which the rim seals, not shown, of theregenerator would cooperate.

The spiral wraps of sheet 22 of rim 20, whether used as a rim, per se,or as a connector, will provide circumferential (tangential) flexibilityand it will readily conform to the inner core 12 with low interfaceloading. Flexibility of the structure of rim 20 is provided by thegeometry of the corrugated strip sheet 22 which permits elasticdistortion within the yield strength of the material of sheet 22.

Although the flexible rim 20, of the invention, is shown on the outerpereiphery of an axial flow matrix, it should be relaized that it isapplicable to use on a radial flow matrix.

What is claimed is:

l. A rotary regenerator matrix including an annular body of heattransfer material of a structure porous to fluid flow through the bodyand adapted to receive heat from a fluid flowing through the body, storeheat, and to deliver heat to a fluid flowing through the body and, aflexible rim of a spirally wrapped, corrugated sheet encircling saidbody, the spiral wraps of said corrugated sheet being bonded to eachother and to said body, the peaks of the corrugations of said corrugatedsheet being crushed in paths angled across a plurality of corrugationsand extending from one edge of said corrugated sheet thereacross.

2. A rotary regenerator matrix according to claim 1 further including arigid rim encircling said flexible rim and connected thereto forrotation therewith, said flexible rim providing a circumferentialflexible connection between said body and said rigid rim.

3. A flexible rim on the annular main heat transfer body of a rotaryregenerator matrix comprising a corrugated sheet having deep,substantially straight, parallel, regular and curved ridges and hollows,the peaks of said ridges being partially crushed in paths angled acrossa plurality of corrugations and extending from one edge of saidcorrugated sheet to the opposite edge of said sheet, said corrugatedsheet with said crushed peaks being spirally wound about said main heattransfer body in a plurality of wraps with said wraps of said corrugatedsheet being secured together and to said main heat transfer body, saidridges and said hollows of said corrugated sheet extending substantiallyparallel to the axis of said main heat transfer body.

4. A rotary regenerator matrix structure of annular form porous to flowof fluid generally parallel to the axis of the matrix and effective toblock fluid flow circumferentially around the axis, said matrixstructure including a first annular section comprising first and secondspiral wound strips with each turn of said first strip disposed betweenadjacent turns of said second strip and with said strips abutting faceto face and fixed together into a rigid, elastic structure, said firststrips having corrugations trending generally axially of the matrix andwith substantial depth radially of said matrix to separate radially theturns of said second strip and define fluid flow passages through saidcorrugations, said second strip having corrugations parallel to those ofsaid first strip and of relatively small depth compared to those of saidfirst strip and, a second section annular comprising spiral wraps ofsaid first strip, with the peaks of the corrugations of said first stripcrushed in paths angled across a plurality of corrugations and extendingfrom one edge of said first strip to the opposite side of said firststrip, said first strip with said crushed paths thereon being spirallywrapped at least two turns in abutting face to face relation and fixedtogether into a rigid, circumferentially flexible rim for said firstsection.

5. A rotary regenerator matrix structure according to claim 4 furtherincluding a rigid rim encircling said second section of said matrix andconnected thereto for rotation therewith, said second section of saidmatrix providing a circumferentially flexible connection between saidfirst section of said matrix and said rigid rim.

6. A rotary regenerator matrix comprising, in combination, an annularbody of heat transfer material of structure pervious to fluid flowthrough the body and adapted to receive heat from a fluid flowingthrough the body, store heat, and deliver heat to a fluid flowingthrough the body, a rigid rim extending circumferentially of said bodyadjacent to but spaced from the outer peripheral surface thereof, and aninterconnecting flexible rim coupling said body to said rigid rim andeffectivve to transmit torque between said body and said rigid rim, saidflexible rim comprising at least two wraps of a corrugated sheet havingdeep corrugations with a portion of the peaks of said corrugationscrushed in angled paths across a plurality of corrugations of the sheetwhereby to prevent nesting of the corrugations of one wrap into thecorrugations of the next radially outward wrap of said corrugated sheetforming said flexible rim.

UNITED sTATE PATENT AND TRADEMARK OFFICE GERTIFICATE OF CORRECTIONPATENTNO. 2 3,901,309

D ED I August 25, 1975 INV,ENTOR(5) 1 Glenn W. Thebert It is certifiedthat error appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 1-, line 47, "although" should read Although Column 4- line 63,"cur" should read cru- Column 5, line 21, "pereiphery" should readperiphery Column 6, line 18, "section annu lar" should read annularsection and,

Column 6, li-ne 44, "effectivve" shoulcl read effective Signed andScaled this sixth Day of April1976 [SEAL] Attest:

RUTH. C. MASON C. MARSHALL DANN Arresting Officer Commissionervj'Patents and Trademarks

1. A rotary regenerator matrix including an annular body of heattransfer material of a structure porous to fluid flow through the bodyand adapted to receive heat from a fluid flowing through the body, storeheat, and to deliver heat to a fluid flowing through the body and, aflexible rim of a spirally wrapped, corrugated sheet encircling saidbody, the spiral wraps of said corrugated sheet being bonded to eachother and to said body, the peaks of the corrugations of said corrugatedsheet being crushed in paths angled across a plurality of corrugationsand extending from one edge of said corrugated sheet thereacross.
 2. Arotary regenerator matrix according to claim 1 further including a rigidrim encircling said flexible rim and connected thereto for rotationtherewith, said flexible rim providing a circumferential flexibleconnection between said body and said rigid rim.
 3. A flexible rim onthe annular main heat transfer body of a rotary regenerator matrixcomprising a corrugated sheet having deep, substantially straight,parallel, regular and curved ridges and hollows, the peaks of saidridges being partially crushed in paths angled across a plurality ofcorrugations and extending from one edge of said corrugated sheet to theopposite edge of said sheet, said corrugated sheet with said crushedpeaks being spirally wound about said main heat transfer body in aplurality of wraps with said wraps of said corrugated sheet beingsecured together and to said main heat transfer body, said ridges andsaid hollows of said corrugated sheet extending substantially parallelto the axis of said main heat transfer body.
 4. A rotary regeneratormatrix structure of annular form porous to flow of fluid generallyparallel to the axis of the matrix and effective to block fluid flowcircumferentially around the axis, said matrix structure including afirst annular section comprising first and second spiral wound stripswith each turn of said first strip disposed between adjacent turns ofsaid second strip and with said strips abutting face to face and fixedtogether into a rigid, elastic structure, said first strips havingcorrugations trending generally axially of the matrix and withsubstantial depth radially of said matrix to separate radially the turnsof said second strip and define fluid flow passages through saidcorrugations, said second strip having corrugations parallel to those ofsaid first strip and of relatively small depth compared to those of saidfirst strip and, a second section annular comprising spiral wraps ofsaid first strip, with the peaks of the corrugations of said first stripcrushed in paths angled across a plurality of corrugations and extendingfrom one edge of said first strip to the opposite side of said firststrip, said first strip with said crushed paths thereon being spirallywrapped at least two turns in abutting face to face relation and fixedtogether into a rigid, circumferentially flexible rim for said firstsection.
 5. A rotary regenerator matrix structure according to claim 4further including a rigid rim encircling said second section of saidmatrix and connected thereto for rotation therewith, said second sectionof said matrix providing a circumferentially flexible connection betweensaid first section of said matrix and said rigid rim.
 6. A rotaryregenerator matrix comprising, in combination, an annular body of heattransfer material of structure pervious to fluid flow through the bodyand adapted to receive heat from a fluid flowing through the body, storeheat, and deliver heat to a fluid flowing through the body, a rigid rImextending circumferentially of said body adjacent to but spaced from theouter peripheral surface thereof, and an interconnecting flexible rimcoupling said body to said rigid rim and effectivve to transmit torquebetween said body and said rigid rim, said flexible rim comprising atleast two wraps of a corrugated sheet having deep corrugations with aportion of the peaks of said corrugations crushed in angled paths acrossa plurality of corrugations of the sheet whereby to prevent nesting ofthe corrugations of one wrap into the corrugations of the next radiallyoutward wrap of said corrugated sheet forming said flexible rim.